Experimental investigation on laser milling of PMMA sheet

In the present paper, laser milling tests were carried out by etching pockets of 10×10 mm2 on the surface of poly-methyl-methacrylate (PMMA) plate, 3 mm in thickness, using a 30 W CO2 laser source, working in continuous or pulsed regime. Aim of the work is to characterize the laser milling process; or rather, to detect which and how the process parameters affect the depth of machined volume, the removed volume and the surface roughness. The milling tests were carried out changing the released energy, the wave mode (CW or PW), the scan speed, the distance between the linear patterns of two consecutive laser scans (step), the number of repetitions of the geometric pattern. Experimental results have shown that the depth and the machined volume linearly depend on the total amount of released energy. Furthermore, the surface roughness has been evaluated and discussed too.